1. Field
Example embodiments relate to a current-mode semiconductor integrated circuit, for example, to a semiconductor integrated circuit device that operates in a current mode during a general operation mode but may operate in a voltage mode during a test mode.
2. Description of the Related Art
A semiconductor device may exchange data with another semiconductor device by using a voltage signal or a current signal. A semiconductor device transmitting and receiving data via a voltage signal may be referred to as a voltage-mode semiconductor device, and a semiconductor device transmitting and receiving data via a current signal may be referred to as a current-mode semiconductor device. To operate a semiconductor device at higher speeds, data may be transmitted via a current signal, not a voltage signal.
An EDS tester and other types of testers (not shown) generally supply a voltage signal to a semiconductor device, which may be referred to as a device under test (DUT), in order to test the semiconductor device. Semiconductor devices are tested by a voltage-mode tester because a voltage-mode tester may be cheaper than a current-mode tester and may reduce or minimize measurement errors. However, some semiconductor chips are designed to operate in a current mode so that they may be driven or operate at higher speeds.
In order to test a semiconductor device operating in a current mode, a measuring device that supplies a current signal to the semiconductor device and measures data output from the semiconductor device in the form of a current signal is needed. However, in general, signal transmission in most common chips is performed in the voltage mode, and signal measurement is also performed in the voltage mode. For this reason, current-mode testers are difficult to apply in most cases, and an additional module capable of measuring current must be provided.
The additional module, however, may increase manufacturing costs, and may require a device that provides an interface between the module and a DUT. Also, the additional module may require time to perform a verification process, thereby increasing the total test time.
Also, a voltage-mode measuring device may be connected to the DUT in parallel to supply a voltage signal to or receive a voltage signal from the DUT, whereas a current-mode measuring device is connected to the DUT in series. Therefore, use of the current-mode measuring device may change the input/output loading on the DUT, thereby degrading test performance.